4r70W p0720,p0722 issues

[RedRobin]

Ok so I bought this 2002 Eddie Bauer with 141k miles with p0720 ,722 code, she runs/shifts perfectly with sensor unplugged but once I plug it back in she starts running like crap, speedo goes to 100 while I'm driving at 20mph and then goes limp. I replaced the OSS and still get that problem so I'm stumped as to what else it could be. I've searched the forum but couldn't find anything that would correlate with my issue.

 

[Hamfisted]

I assume you checked the fluid level warm and it's good. I would closely inspect the wiring harness and plug for the sensor. Sounds like it's possibly shorting to ground. Make sure it didn't chaff or burn through on an exhaust pipe. How long have you had the Expy ?








.

 

[RedRobin]

I’ve only had it for 2 weeks

 

[RedRobin]

ok so I took the harness off yesterday Saturday I checked all the wires from plug to plug and all of them were good , no signs of fraying or burnt wires. I'm completely stumped on this one don't know what else to look for.

 

[whtbronco]

Did you happen to check for continuity on each of the wires in the harness? Also make sure there aren't any broken or bent pins in the connectors.

You may need to get a high end OBDII scanner or FORScan. This will help with verifying there is output and then reading the output from the speed sensor.